Single Tau-Shaped Anterolateral Thigh Free Flap on Bimalleolar Defect Acquired by Osteomyelitis in Lower Extremity Trauma: A Case Report

Abstract

Soft tissue defects can cause serious issues in traumatic lower extremity injuries when limb salvage is the goal, especially when complicated by osteomyelitis. The distal lower extremities lack redundant soft tissue, necessitating free tissue transfer for complex injury reconstruction. For bimalleolar defects, a chimeric or double flap is an option, but harvesting such flaps can be challenging, and multiple arterial anastomoses risks distal limb ischemia. We present a case of a large bimalleolar defect with associated osteomyelitis covered with a single anterolateral thigh (ALT) free flap. Preoperative mapping identified perforator distribution allowing design of a single tau-shaped flap from the left thigh to minimize morbidity. The defects were covered successfully with no permanent complications. Given the ALT flap’s consistent anatomy, this case could guide future approaches for typical bimalleolar defects, including those with osteomyelitis.